l3 (18may16)

git-svn-id: svn://tug.org/texlive/trunk@41246 c570f23f-e606-0410-a88d-b1316a301751

3 files changed, 472 insertions, 15 deletions

diff --git a/Master/texmf-dist/source/latex/l3kernel/expl3.dtx b/Master/texmf-dist/source/latex/l3kernel/expl3.dtx
index 165d2dc1762..5a97f7632e7 100644
--- a/Master/texmf-dist/source/latex/l3kernel/expl3.dtx
+++ b/Master/texmf-dist/source/latex/l3kernel/expl3.dtx
@@ -36,8 +36,8 @@
 %<*driver|generic|package>
 \def\ExplFileName{expl3}%
 \def\ExplFileDescription{L3 programming layer}%
-\def\ExplFileDate{2016/05/14}%
-\def\ExplFileVersion{6495}%
+\def\ExplFileDate{2016/05/18}%
+\def\ExplFileVersion{6512}%
 %</driver|generic|package>
 %<*driver>
 \documentclass[full]{l3doc}
diff --git a/Master/texmf-dist/source/latex/l3kernel/l3coffins.dtx b/Master/texmf-dist/source/latex/l3kernel/l3coffins.dtx
index 22f322f2498..7923f0f1695 100644
--- a/Master/texmf-dist/source/latex/l3kernel/l3coffins.dtx
+++ b/Master/texmf-dist/source/latex/l3kernel/l3coffins.dtx
@@ -38,7 +38,7 @@
 \documentclass[full]{l3doc}
 %</driver>
 %<*driver|package>
-\GetIdInfo$Id: l3coffins.dtx 6440 2016-03-24 09:59:29Z joseph $
+\GetIdInfo$Id: l3coffins.dtx 6508 2016-05-17 17:00:42Z joseph $
   {L3 Coffin code layer}
 %</driver|package>
 %<*driver>
@@ -646,7 +646,7 @@
             \dim_set_eq:NN \linewidth   \tex_hsize:D
             \dim_set_eq:NN \columnwidth \tex_hsize:D
 %</package>
-          \color_group_begin: \color_ensure_current:
+          \color_group_begin:
           \cs_set_protected:Npn \vcoffin_set_end:
             {
                 \color_group_end:
diff --git a/Master/texmf-dist/source/latex/l3kernel/l3drivers.dtx b/Master/texmf-dist/source/latex/l3kernel/l3drivers.dtx
index 24252e7ae45..cfbcb9bdce3 100644
--- a/Master/texmf-dist/source/latex/l3kernel/l3drivers.dtx
+++ b/Master/texmf-dist/source/latex/l3kernel/l3drivers.dtx
@@ -38,7 +38,7 @@
 \documentclass[full]{l3doc}
 %</driver>
 %<*driver|package>
-\GetIdInfo$Id: l3drivers.dtx 6494 2016-05-14 21:10:56Z joseph $
+\GetIdInfo$Id: l3drivers.dtx 6511 2016-05-17 20:20:23Z joseph $
   {L3 Experimental drivers}
 %</driver|package>
 %<*driver>
@@ -153,6 +153,214 @@
 %   while preserving the color used in the box.
 % \end{function}
 %
+% \section{Drawing}
+%
+% The drawing functions provided here are \emph{highly} experimental. They
+% are inspired heavily by the system layer of \pkg{pgf} (most have the
+% same interface as the same functions in the latter's \cs{pgfsys@\ldots}
+% namespace). They are intended to form the basis for higher level drawing
+% interfaces, which themselves are likely to be further abstracted for user
+% access. Again, this model is heavily inspired by \pkg{pgf} and
+% Ti\textit{k}z.
+%
+% These low level drawing interfaces abstract from the driver raw requirements
+% but still require an appreciation of the concepts of PostScript/PDF/SVG
+% graphic creation.
+%
+% At present \emph{not all drivers are covered} by the following.
+%
+% \begin{function}
+%   { \__driver_draw_begin:,  \__driver_draw_end:}
+%   \begin{syntax}
+%     \cs{__driver_draw_begin:}
+%     \meta{content}
+%     \cs{__driver_draw_end:}
+%   \end{syntax}
+%   Defines a drawing environment. This will be a scope for the purposes of
+%   the graphics state. Depending on the driver, other set up may or may not
+%   take place here. The natural size of the \meta{content} should be zero
+%   from the \TeX{} perspective: allowance for the size of the content must
+%   be made at a higher level (or indeed this can be skipped if the content is
+%   to overlap other material).
+% \end{function}
+%
+% \begin{function}
+%   {\__driver_draw_scope_begin:,  \__driver_draw_scope_end:}
+%   \begin{syntax}
+%     \cs{__driver_draw_scope_begin:}
+%     \meta{content}
+%     \cs{__driver_draw_scope_end:}
+%   \end{syntax}
+%   Defines a scope for drawing settings and so on. Changes to the graphic
+%   state and concepts such as color or linewidth are localised to a scope.
+%   This function pair must never be used if an partial path is under
+%   construction: such paths must be entirely contained at one unbroken
+%   scope level.
+% \end{function}
+%
+% \subsection{Path construction}
+%
+% \begin{function}{\__driver_draw_moveto:nn}
+%   \begin{syntax}
+%     \cs{__driver_draw_move:nn} \Arg{x} \Arg{y}
+%   \end{syntax}
+%   Moves the current drawing reference point to (\meta{x}, \meta{y});
+%   any active transformation matrix will apply.
+% \end{function}
+%
+% \begin{function}{\__driver_draw_lineto:nn}
+%   \begin{syntax}
+%     \cs{__driver_draw_lineto:nn} \Arg{x} \Arg{y}
+%   \end{syntax}
+%   Adds a path from the current drawing reference point to
+%   (\meta{x}, \meta{y}); any active transformation matrix will apply. Note
+%   that nothing is drawn until a fill or stroke operation is applied, and that
+%   the path may be discarded or used as a clip without appearing itself.
+% \end{function}
+%
+% \begin{function}{\__driver_draw_curveto:nnnnnn}
+%   \begin{syntax}
+%     \cs{__driver_draw_curveto:nnnnnn} \Arg{x_1} \Arg{y_1}
+%       \Arg{x_2} \Arg{y_2} \Arg{x_3} \Arg{y_3}
+%   \end{syntax}
+%   Adds a Bezier curve path from the current drawing reference point to
+%   (\meta{x_3}, \meta{y_3}), using (\meta{x_1}, \meta{y_1}) and
+%   (\meta{x_2}, \meta{y_2}) as control points; any active transformation
+%   matrix will apply.  Note that nothing is drawn until a fill or stroke
+%   operation is applied, and that the path may be discarded or used as a clip
+%   without appearing itself.
+% \end{function}
+%
+% \begin{function}{\__driver_draw_closepath:}
+%   \begin{syntax}
+%     \cs{__driver_draw_closepath:}
+%   \end{syntax}
+%   Closes an existing path, adding a line from the current point to the
+%   start of path. Note that nothing is drawn until a fill or stroke
+%   operation is applied, and that the path may be discarded or used as a clip
+%   without appearing itself.
+% \end{function}
+%
+% \subsection{Stroking and filling}
+%
+% \begin{function}{\__driver_draw_stroke:, \__driver_draw_closestroke:}
+%   \begin{syntax}
+%     \meta{path construction}
+%     \cs{__driver_draw_stroke:}
+%   \end{syntax}
+%   Draws a line alone the current path, which will also be closed when
+%   \cs{__driver_draw_closestroke:} is used. The nature of the line drawn
+%   is influenced by settings for
+%   \begin{itemize}
+%     \item Line thickness
+%     \item Stroke color (or the current color if no specific stroke color
+%       is set)
+%     \item Line capping (how non-closed line ends should look)
+%     \item Join style (how a bend in the path should be rendered)
+%     \item Dash pattern
+%   \end{itemize}
+%   The path may also be used for clipping.
+% \end{function}
+%
+% \begin{function}{\__driver_draw_fill:, \__driver_draw_fillstroke:}
+%   \begin{syntax}
+%     \meta{path construction}
+%     \cs{__driver_draw_fill:}
+%   \end{syntax}
+%   Fills the area surrounded by the current path: this will be closed prior
+%   to filling if it is not already. The \texttt{fillstroke} version will also
+%   stroke the path as described for \cs{__driver_draw_stroke:}. The fill is
+%   influenced by the setting for fill color (or the current color if no
+%   specific stroke color is set). The path may also be used for clipping.
+%   For paths which are self-intersecting or comprising multiple parts, the
+%   determination of which areas are inside the path is made using the nonzero
+%   winding rule number unless \cs{__driver_draw_eor_bool} is \texttt{true},
+%   in which case the even-odd rule is used.
+% \end{function}
+%
+% \begin{function}{\__driver_draw_clip:}
+%   \begin{syntax}
+%     \meta{path construction}
+%     \cs{__driver_draw_clip:}
+%   \end{syntax}
+%   Indicates that the current path should be used for clipping, such that
+%   any subsequent material outside of the path (but within the current
+%   scope) will not be shown. This command should be given once a path is
+%   complete but before it is stroked or filled (if appropriate).
+% \end{function}
+%
+% \begin{function}{\__driver_draw_discardpath:}
+%   \begin{syntax}
+%     \meta{path construction}
+%     \cs{__driver_draw_discardpath:}
+%   \end{syntax}
+%   Discards the current path without stroking or filling. This is primarily
+%   useful for paths constructed purely for clipping, as this alone does not
+%   end the paths existence.
+% \end{function}
+%
+% \subsection{Stroke options}
+%
+% \begin{function}{\__driver_draw_linewidth:n}
+%   \begin{syntax}
+%     \cs{__driver_draw_linewidth:n} \Arg{dimexpr}
+%   \end{syntax}
+%   Sets the width to be used for stroking to \meta{dimexpr}.
+% \end{function}
+%
+% \begin{function}{\__driver_draw_dash:nn}
+%   \begin{syntax}
+%     \cs{__driver_draw_dash:nn} \Arg{dash pattern} \Arg{phase}
+%   \end{syntax}
+%   Sets the pattern of dashing to be used when stroking a line. The
+%   \meta{dash pattern} should be a comma-separated list of dimension
+%   expressions. This is then interpreted as a series of pairs of line-on
+%   and line-off lengths. For example \texttt{3pt, 4pt} means that $3$\,pt on,
+%   $4$\,pt off, $3$\,pt on, and so on. A more complex pattern will also
+%   repeat: \texttt{3pt, 4pt, 1pt, 2pt} results in $3$\,pt on, $4$\,pt off,
+%   $1$\,pt on, $2$\,pt off, $3$\,pt on, and so on. An odd number of entries
+%   means that the last is repeated, for example \texttt{3pt} is equal to
+%   \texttt{3pt, 3pt}. An empty pattern yields a solid line.
+%   
+%   The \meta{phase} specifies an offset at the start of the cycle. For
+%   example, with a pattern \texttt{3pt} a phase of \texttt{1pt} will mean
+%   that the output is $2$\,pt on, $3$\,pt off, $3$\,pt on, $3$\,pt on,
+%   \emph{etc.}
+% \end{function}
+%
+% \begin{function}
+%   {
+%     \__driver_draw_cap_butt:      ,
+%     \__driver_draw_cap_rectangle: ,
+%     \__driver_draw_cap_round:
+%   }
+%   \begin{syntax}
+%     \cs{__driver_draw_cap_butt:}
+%   \end{syntax}
+%   Sets the style of terminal stroke position to one of butt, rectangle or
+%   round.
+% \end{function}
+%
+% \begin{function}
+%   {
+%     \__driver_draw_join_bevel:      ,
+%     \__driver_draw_join_miter: ,
+%     \__driver_draw_join_round:
+%   }
+%   \begin{syntax}
+%     \cs{__driver_draw_cap_butt:}
+%   \end{syntax}
+%   Sets the style of stroke joins to one of bevel, miter or round.
+% \end{function}
+%
+% \begin{function}{\__driver_draw_miterlimit:n}
+%   \begin{syntax}
+%     \cs{__driver_draw_miterlimit:n} \Arg{dimexpr}
+%   \end{syntax}
+%   Sets the miter limit of lines joined as a miter, as described in the
+%   PDF and PostScript manuals.
+% \end{function}
+%
 % \end{documentation}
 %
 % \begin{implementation}
@@ -383,12 +591,12 @@
 % \begin{macro}[aux]{\@@_color_reset:}
 %   Directly set the color using the specials with optimisation support.
 %    \begin{macrocode}
-\cs_new_protected_nopar:Npx \@@_color_ensure_current:
+\cs_new_protected_nopar:Npn \@@_color_ensure_current:
   {
     \tex_special:D { pdf:bcolor~\l_@@_current_color_tl }
-    \group_insert_after:N \exp_not:N \@@_color_reset:
+    \group_insert_after:N \@@_color_reset:
   }
-\cs_new_protected_nopar:Npx \@@_color_reset:
+\cs_new_protected_nopar:Npn \@@_color_reset:
   { \tex_special:D { pdf:ecolor } }
 %    \end{macrocode}
 % \end{macro}
@@ -419,9 +627,8 @@
         \cs_set_protected_nopar:Npn \@@_color_ensure_current:
           {
             \tex_special:D { color~push~\l_@@_current_color_tl }
-            \group_insert_after:N \exp_not:N \@@_color_reset:
+            \group_insert_after:N \@@_color_reset:
           }
-
         \cs_set_protected_nopar:Npn \@@_color_reset:
           { \tex_special:D { color~pop } }
       }
@@ -533,6 +740,258 @@
 %    \end{macrocode}
 % \end{macro}
 %
+% \subsection{Drawing}
+%
+% \begin{macro}[aux]{\@@_draw_literal:n, \@@_draw_literal:x}
+%   Pass data through using a dedicated interface.
+%     \begin{macrocode}
+\cs_new_eq:NN \@@_draw_literal:n \@@_literal:n
+\cs_generate_variant:Nn \@@_draw_literal:n { x }
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}[int]{\@@_draw_begin:, \@@_draw_end:}
+%   No special requirements here, so simply set up a drawing scope.
+%     \begin{macrocode}
+\cs_new_protected_nopar:Npn \@@_draw_begin:
+  { \@@_draw_scope_begin: }
+\cs_new_protected_nopar:Npn \@@_draw_end:
+  { \@@_draw_scope_end: }
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}[int]{\@@_draw_scope_begin:, \@@_draw_scope_end:}
+%   In contrast to a general scope, a drawing scope is always done using
+%   the PDF operators so is the same for all relevant drivers.
+%     \begin{macrocode}
+\cs_new_protected_nopar:Npn \@@_draw_scope_begin:
+  { \@@_draw_literal:n { q } }
+\cs_new_protected_nopar:Npn \@@_draw_scope_end:
+  { \@@_draw_literal:n { Q } }
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}[int]{\@@_draw_moveto:nn, \@@_draw_lineto:nn}
+% \begin{macro}[int]{\@@_draw_curveto:nnnnnn}
+%   Path creation operations all resolve directly to PDF primitive steps, with
+%   only the need to convert to \texttt{bp}. Notice that \texttt{x}-type
+%   expansion is included here to ensure that any variable values are
+%   forced to literals before any possible caching.
+%     \begin{macrocode}
+\cs_new_protected:Npn \@@_draw_moveto:nn #1#2
+  {
+    \@@_draw_literal:x
+      { \dim_to_decimal_in_bp:n {#1} ~ \dim_to_decimal_in_bp:n {#2} ~ m }
+  }
+\cs_new_protected:Npn \@@_draw_lineto:nn #1#2
+  {
+    \@@_draw_literal:x
+      { \dim_to_decimal_in_bp:n {#1} ~ \dim_to_decimal_in_bp:n {#2} ~ l }
+  }
+\cs_new_protected:Npn \@@_draw_curveto:nnnnnn #1#2#3#4#5#6
+  {
+    \@@_draw_literal:x
+      {
+        \dim_to_decimal_in_bp:n {#1} ~ \dim_to_decimal_in_bp:n {#2} ~
+        \dim_to_decimal_in_bp:n {#3} ~ \dim_to_decimal_in_bp:n {#4} ~
+        \dim_to_decimal_in_bp:n {#5} ~ \dim_to_decimal_in_bp:n {#6} ~
+        c
+      }
+ }
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{variable}[int]{\@@_draw_eor_bool}
+%    The even-odd rule here can be implemented as a simply switch.
+%     \begin{macrocode}
+\bool_new:N \@@_draw_eor_bool
+%    \end{macrocode}
+% \end{variable}
+%
+% \begin{macro}[int]
+%   {
+%     \@@_draw_closepath:   ,
+%     \@@_draw_stroke:      ,
+%     \@@_draw_closestroke: ,
+%     \@@_draw_fill:        ,
+%     \@@_draw_fillstroke:  ,
+%     \@@_draw_clip:        ,
+%     \@@_draw_discardpath:
+%   }
+%   Converting paths to output is again a case of mapping directly to
+%   PDF operations.
+%     \begin{macrocode}
+\cs_new_protected_nopar:Npn \@@_draw_closepath:
+  { \@@_draw_literal:n { h } }
+\cs_new_protected_nopar:Npn \@@_draw_stroke:
+  { \@@_draw_literal:n { S } }
+\cs_new_protected_nopar:Npn \@@_draw_closestroke:
+  { \@@_draw_literal:n { s } }
+\cs_new_protected_nopar:Npn \@@_draw_fill:
+  {
+    \@@_draw_literal:x
+      { f \bool_if:NT \@@_draw_eor_bool * }
+  }
+\cs_new_protected_nopar:Npn \@@_draw_fillstroke:
+  {
+    \@@_draw_literal:x
+      { B \bool_if:NT \@@_draw_eor_bool * }
+  }
+\cs_new_protected_nopar:Npn \@@_draw_clip:
+  {
+    \@@_draw_literal:x
+      { W \bool_if:NT \@@_draw_eor_bool * }
+  }
+\cs_new_protected_nopar:Npn \@@_draw_discardpath:
+  { \@@_draw_literal:n { n } }
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}[int]{\@@_draw_dash:nn}
+% \begin{macro}[aux]{\@@_draw_dash:n}
+% \begin{macro}[int]{\@@_draw_linewidth:n}
+% \begin{macro}[int]{\@@_draw_miterlimit:n}
+% \begin{macro}[int]^^A
+%   {
+%     \@@_draw_cap_butt:, \@@_draw_cap_round:, \@@_draw_cap_rectangle:,
+%     \@@_draw_join_miter:, \@@_draw_join_round:, \@@_draw_join_bevel:
+%   }
+%   Converting paths to output is again a case of mapping directly to
+%   PDF operations.
+%     \begin{macrocode}
+\cs_new_protected:Npn \@@_draw_dash:nn #1#2
+  {
+    \@@_draw_literal:x
+      {
+        [ ~
+          \clist_map_function:nN {#1} \@@_draw_dash:n
+        ] ~
+        \dim_to_decimal_in_bp:n {#2} ~ d
+      }
+  }
+\cs_new:Npn \@@_draw_dash:n #1
+  { \dim_to_decimal_in_bp:n {#1} ~ }
+\cs_new_protected:Npn \@@_draw_linewidth:n #1
+  {
+    \@@_draw_literal:x
+      { \dim_to_decimal_in_bp:n {#1} ~ w }
+  }
+\cs_new_protected:Npn \@@_draw_miterlimit:n #1
+  { \@@_draw_literal:x { \fp_eval:n {#1} ~ M } }
+\cs_new_protected_nopar:Npn \@@_draw_cap_butt:
+  { \@@_draw_literal:n { 0 ~ J } }
+\cs_new_protected_nopar:Npn \@@_draw_cap_round:
+  { \@@_draw_literal:n { 1 ~ J } }
+\cs_new_protected_nopar:Npn \@@_draw_cap_rectangle:
+  { \@@_draw_literal:n { 2 ~ J } }
+\cs_new_protected_nopar:Npn \@@_draw_join_miter:
+  { \@@_draw_literal:n { 0 ~ j } }
+\cs_new_protected_nopar:Npn \@@_draw_join_round:
+  { \@@_draw_literal:n { 1 ~ j } }
+\cs_new_protected_nopar:Npn \@@_draw_join_bevel:
+  { \@@_draw_literal:n { 2 ~ j } }
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}[int]
+%   {\@@_draw_color_cmyk_fill:nnnn, \@@_draw_color_cmyk_stroke:nnnn}
+% \begin{macro}[int]
+%   {\@@_draw_color_gray_fill:n, \@@_draw_color_gray_stroke:n}
+% \begin{macro}[int]
+%   {\@@_draw_color_rgb_fill:nnn, \@@_draw_color_rgb_stroke:nnn}
+%   Yet more fast conversion, all using the FPU to allow for expressions
+%   in numerical input.
+%     \begin{macrocode}
+\cs_new_protected:Npn \@@_draw_color_cmyk_fill:nnnn #1#2#3#4
+  {
+    \@@_draw_literal:x
+      {
+        \fp_eval:n {#1} ~ \fp_eval:n {#2} ~
+        \fp_eval:n {#3} ~ \fp_eval:n {#4} ~
+        k
+      }
+  }
+\cs_new_protected:Npn \@@_draw_color_cmyk_stroke:nnnn #1#2#3#4
+  {
+    \@@_draw_literal:x
+      {
+        \fp_eval:n {#1} ~ \fp_eval:n {#2} ~
+        \fp_eval:n {#3} ~ \fp_eval:n {#4} ~
+        K
+      }
+  }
+\cs_new_protected:Npn \@@_draw_color_gray_fill:n #1
+  { \@@_draw_literal:x { \fp_eval:n {#1} ~ g } }
+\cs_new_protected:Npn \@@_draw_color_gray_stroke:n #1
+  { \@@_draw_literal:x { \fp_eval:n {#1} ~ G } }
+\cs_new_protected:Npn \@@_draw_color_rgb_fill:nnn #1#2#3
+  {
+    \@@_draw_literal:x
+      { \fp_eval:n {#1} ~ \fp_eval:n {#2} ~ \fp_eval:n {#3} ~ rg }
+  }
+\cs_new_protected:Npn \@@_draw_color_rgb_stroke:nnn #1#2#3
+  {
+    \@@_draw_literal:x
+      { \fp_eval:n {#1} ~ \fp_eval:n {#2} ~ \fp_eval:n {#3} ~ RG }
+  }
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}[int]{\@@_draw_transformcm:nnnnnn}
+%   The first four arguments here are floats (the affine matrix), the last
+%   two are a displacement vector. Once again, force evaluation to allow for
+%   caching.
+%     \begin{macrocode}
+\cs_new_protected:Npn \@@_draw_transformcm:nnnnnn #1#2#3#4#5#6
+  {
+    \@@_draw_literal:x
+      {
+        \fp_eval:n {#1} ~ \fp_eval:n {#2} ~
+        \fp_eval:n {#3} ~ \fp_eval:n {#4} ~
+        \dim_to_decimal_in_bp:n {#5} ~ \dim_to_decimal_in_bp:n {#6} ~
+        cm
+      }
+  }
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}[int]{\@@_draw_hbox:Nnnnnnn}
+% \begin{variable}[aux]{\l_@@_tmp_box}
+%   Inserting a \TeX{} box transformed to the requested position and using
+%   the current matrix is done using a mixture of \TeX{} and low-level
+%   manipulation. The offset can be handled by \TeX{}, so only any rotation/^^A
+%   skew/scaling component needs to be done using the matrix operation. As this
+%   operation can never be cached, the scope is set directly not using the
+%   \texttt{draw} version.
+%     \begin{macrocode}
+\cs_new_protected:Npn \@@_draw_hbox:Nnnnnnn #1#2#3#4#5#6#7
+  {
+    \hbox_set:Nn \l_@@_tmp_box
+      {
+        \tex_kern:D \__dim_eval:w #6 \__dim_eval_end:
+        \@@_scope_begin:
+        \@@_draw_transformcm:nnnnnn {#2} {#3} {#4} {#5}
+          { 0pt } { 0pt }
+        \box_move_up:nn {#7} { \box_use:N #1 }
+        \@@_scope_end:
+      }
+    \box_set_wd:Nn \l_@@_tmp_box { 0pt }
+    \box_set_ht:Nn \l_@@_tmp_box { 0pt }
+    \box_set_dp:Nn \l_@@_tmp_box { 0pt }
+    \box_use:N \l_@@_tmp_box
+  }
+\box_new:N \l_@@_tmp_box
+%    \end{macrocode}
+% \end{variable}
+% \end{macro}
+%
 %    \begin{macrocode}
 %</dvipdfmx|pdfmode|xdvipdfmx>
 %    \end{macrocode}
@@ -552,7 +1011,7 @@
 %   of the stack to save the current position \enquote{up front} and to
 %   move back to it at the end of the process.
 %    \begin{macrocode}
-\cs_new_protected:Npx \@@_literal:n #1
+\cs_new_protected:Npn \@@_literal:n #1
   {
     \tex_special:D
       {
@@ -691,7 +1150,6 @@
     \tex_special:D { color~push~\l_@@_current_color_tl }
     \group_insert_after:N \@@_color_reset:
   }
-
 \cs_new_protected_nopar:Npn \@@_color_reset:
   { \tex_special:D { color~pop } }
 %    \end{macrocode}
@@ -897,9 +1355,8 @@
 \cs_new_protected_nopar:Npn \@@_color_ensure_current:
   {
     \tex_special:D { color~push~\l_@@_current_color_tl }
-    \group_insert_after:N \exp_not:N \@@_color_reset:
+    \group_insert_after:N \@@_color_reset:
   }
-
 \cs_new_protected_nopar:Npn \@@_color_reset:
   { \tex_special:D { color~pop } }
 %    \end{macrocode}
@@ -916,4 +1373,4 @@
 %
 % \end{implementation}
 %
-% \PrintIndex
\ No newline at end of file
+% \PrintIndex